1. Engineering Excellence Awards 2013
“Reverse Osmosis in Aluminium Smelter for
Effluent Treatment”
Vedanta Aluminium Limited, Jharsuguda
1

2. Domestic Aluminium Smelter Scenario
Production in KTPA
Balco (expansion)
325
Balco
Next 5 years Forecast
Production Projections:
245
 Aluminium demand remains healthy
Nalco
460
Lapanga
(Hindalco)
Vedanta Plant1
Vedanta Plant2
359
Mahan Aluminium
Hirakud (Hindalco)
Renukoot (Hindalco)
213
Muri (Hindalco)
Muri (Hindalco)
359
Renukoot
(Hindalco)
400
Mahan Aluminium
359
Hirakud (Hindalco)
Lapanga (Hindalco)
Nalco
Balco
 As per the current greenfield projects,
Aluminium Production is set to be
doubled by next 5 years
 Water consumption rate is approximately
1m3/MT of Al produced. Efficient
recycling techniques required
Balco (expansion)
Vedanta Plant2
1100
Vedanta Plant1
500
0
 The raw effluent coming from the plant
contains up to 50 ppm fluoride
500 1000 1500
In Production – 1918 KTPA
Greenfield – 2402 KTPA
2

3. Smelter Process Scenario
Cast Metal
Air Emission
Raw Material
Aluminium
Smelter
+
Power
Solid Waste
Waste Water
Raw Material
Alumina:
Al2O3
Carbon Anode:
C
Cryolite:
Na3AlF6
Aluminium Fluoride: AlF3
Raw Effluent
3

4. Major Objectives of Effluent Treatment
 Zero discharge of rejected effluents to ambient water
 Treating effluents to fresh water levels. Hence Conservation of
water
4

5. Types of Effluent Treatment Techniques
Nalgonda
Technique
Adsorption
Technique
Reverse Osmosis
Ion Exchange
Method
Distillation
Process
5

6. Why Reverse Osmosis ??
Fluoride removal efficiency > 99%
Membrane Separation Technology without using
Chemicals
Less area for operation
Removes other biological impurities
6

7. Process flow diagram of Effluent Treatment Plant
50
50
7

8. Preliminary Treatment
Rated Capacity: 100m3/hour x 3

The effluent recycling plant is designed to treat 250 m3/day of effluent.

The rejects of the ETP are disposed of to a sludge drying bed by back flush in the system. The
sludge is further disposed off in SLF area.
8

9. Sand Filtration and Iron Removal
Pressure Sand Filter
Rate : 50 m3/hour
It is used to remove the suspended
solids in the effluent
Iron Removal Filter
Rate : 50 m3/hour
It is used to remove the iron particles in
the effluent
9

10. Ultrafiltration & Double Stage RO
Ultra Filtration
Rate: 50 m3/hour
The mesh size of RO
membrane is 0.01 microns
 UF consists of hydranautics membrane fitted with PLC based system for automatic
service.
 The main function of this system is to reduce BOD, COD, biological
impurities, suspended solids and oil from the effluent.
10

11. Treatment by Reverse Osmosis
Principle of Reverse Osmosis

12. Double Stage RO
Reverse Osmosis
Rate: 50 m3/hour
The mesh size of RO
membrane is 0.0001
microns
 RO typically operates at 10-12 bar for reverse high pressure.
 The membranes of RO are semi-permeable.
 It consists of double stage membrane to reduce dissolve impurities and fluoride from
the effluent.
12

13. RO Membranes
Maximum Operating
Temperature –
30 – 35 oC
Life Span – 3 Years
 RO membranes are cellulose acetate, aromatic polyamide and thin film composite (TFC). In
general all TFC membranes are placed in series in a pressure vessel
 Cellulose acetate is resistant to small concentration of chlorine and is therefore kept free from
bacteria and its subsequent re-growth.
 Aromatic polyamide cannot tolerate chlorine but is resistant to bacteria. It is useful in treating
over a wider pH range (4-11) of effluent.

14. Treated Effluent Quality
Effluent
Sand & Iron Removal
TSS
< 1255ppm
7.3 – 8.1
pH
Ultra Filtration
TSS
< 5.0 ppm
7.0 – 7.5
pH
TSS
pH
Reverse Osmosis
< 1.0 ppm
7.0 – 7.5
TSS
pH
< 0.1 ppm
7.0 – 7.5
BOD
< 30 ppm
BOD
< 20 ppm
BOD
< 5 ppm
BOD
< 5 ppm
COD
< 100 ppm
COD
< 90 ppm
COD
< 30 ppm
COD
< 20 ppm
O&G
< 35 ppm
O&G
< 5 ppm
O&G
< 2 ppm
O&G
< BDL
TDS
< 500 ppm
TDS
< 500 ppm
TDS
< 500 ppm
TDS
< 50 ppm
Fluoride
< 50 ppm
Fluoride
< 7 ppm
Fluoride
< 5 ppm
Fluoride
< 1ppm
Iron
< 2.4 ppm
Iron
< 0.3 ppm
Iron
< 0.2 ppm
Iron
< 0.1 ppm
Hardness
< 120 ppm
Hardness
< 120 ppm
Hardness
< 120 ppm
Hardness
< 5 ppm
Raw Effluent
ETP + PSF + IRF
After Ultra Filtration
After Reverse Osmosis
14

15. Water Consumption Scenario
3
700000
598907
584141
600000
2.64
500000
2
2.13
410563
400000
1.74
303833
300000
1.3
1.23
1
0.85
200000
90553
0
100000
0
0
2008-09
2009-10
2010-11
Recycled Water
2011-12
2012-13
2013-14 (YTD)
SWC
15

16. Handling of RO Rejects – Solar Pond
Specifications of Solar Pond
Surface Area – 2000 m2
Tank Depth – 2 meters
Free Board – 0.25 meters
Evaporation rate – 5m3/hour
 Solar pond is used for forced evaporation of rejected RO effluents
 It consist of rectangular concrete tank fitted with specially designed solar
air heating system and mist fans
16

17. Solar Panels & Atomizers
Mist Fans (atomizers)
Solar Heating Panels
Mist Fans
Solar Heating Panels
 The RO reject gets converted into mist
by mist fans.
 They are used to blow hot air to the
solar pond
 It is then evaporated by blowing hot
air with solar air heating system
 It ensures faster evaporation in spite of
being spread over a small surface area.
17

18. Disposal of Rejected Effluents
HAZARDOUS
WASTES
SLF
18

19. Power Consumption
Total Power connected load is 93.2 KW
Total Power consumption is 2236.8 KWH per day
19

20. Benefits of Advanced Solar Pond
Multiple Effect
Evaporator
Normal Solar Pond
m2
Advanced Solar Pond
2000 m2 with a depth of
2m
Surface area
-
O & M cost
Rs 43/m3
Rs 28.9/m3
Rs 10/m3
Evaporation
Rate
3.2 m3/hour
3.3 m3/hour
5 m3/hour
19200
20

21. Key Benefits
100% recycling of water coming in to the system
Consistency in output quality even with varying inputs
It reduces fluoride to < 1 ppm as well as other
pollutants significantly
Can be used to treat any fluoride contaminated water
If adopted by all smelter plants as per present scenario, this can reduce
approximately 2 Mt fluoride load to Environment over conventional
treatment
21

22. Our Vision is to become the Benchmark in
Environmentally Sustainable Aluminium Smelter
22